Saturday 28 October 2017

White-backed Woodpecker on Snežnik

The White-backed Woodpecker Dendrocopos leucotos is one of the rarest breeding birds in Slovenia. Most of the Slovenian population resides in the southern part of the country, in the vast Dinaric forests. These populations belong to the Balkan subspecies lilfordi (named after him), whereas the nominate leucotos has only been observed a couple of times in the Alpine region of Slovenia. White-backed Woodpecker is a beech forest specialits, favouring old stands with large amounts of dead wood; either standing or fallen decaying trees. Although over 58% of Slovenia is forested, most of it is not suitable for this exigent woodpecker. The species has low densities and large territories over vast mountainous areas, hence it is difficult to track and monitor. The best time to observe this species is early spring, when birds are highly territorial and drum, thus are easier to detect. But if visiting the proper habitat, one might be lucky also in autumn...
A few days ago, during a visit to a forest reserve on the Snežnik plateau, we stumbled across this female, feeding on tree stumps close to the ground, not only on beech, but also on old conifers. As it seems to be typical for the species, the bird was feeding quite nervously (unlike other woodpeckers) and kept moving around from one tree to the other (short video). When we lost it for a while, we could then relocate it after about half an hour, thanks to the soft calls it was making. In the meantime it had moved several hundred meters, proving that the species, even in the proper habitat, has quite large territories. The bird then disappeared even farther away, deep into the forest. In the pics, note the barred back, typical of ssp. lilfordi and unlike ssp. leucotos which has a more pure-white back.
The forest was full of White-backed Woodpecker's sings: either "classical" feeding signs (first two above) or old nest-holes on dead standing beech trees (third pic). For feeding the species is reliant on beetle's larvae that bore into the decaying wood. Some studies in Europe have shown that the species' diet includes several rare and endangered forest beetles that share the same primeval forest habitats.
Some views on the forest where we observed the White-backed Woodpecker; clearly the right place for the species. Forest reserves as this one provide an excellent habitat for the species, but are often too small to provide space for a viable and thriving population. Such pockets of preserved forest are frequently disconnected from other similar habitats and they prove insufficent for the woodpecker's conservation on a larger scale. Intensive forest management is a big problem for forest biodiversity in Slovenia, as it is in other parts of the world.
The area where we found the White-back was dominated by beech Fagus sylvatica, although ecotones with spruce Picea abies and silver fir Abies alba forest were also present. These areas of habitat mix are excellent for a variety of species, including the Three-toed Woodpecker Picoides tridactylus that we observed almost simultaneously with the White-back! Having a look around we also noticed good amounts of dead conifer (above) that probably provide an excellent all-year-round territory also for the Three-toed Woodpecker.
The lichen Lobaria pulmonaria, bioindicator of clean and unpolluted air, was very frequent on beech and sycamore Acer pseudoplatanus in the forest reserve. Another sign of the preciousness of this primeval-like forest ecosystems.
The day was excellent also for some sightseeing, so in the afternoon we decided to hike onto the top of mount Snežnik (1796 m). It was a brillinat idea, as the panorama was breathtaking due to the crisp autumn weather. The first two pics above show the view to the south-east, where extensive forests dominate and stretch into Croatia's Gorski kotar, forming the largest forest complex of central and south-eastern Europe. The third pic shows a typical example of temperature inversion doline - a depression where the vegetational belts usually found when ascending a mountain are inverted: the doline's bottom is the coldest part with typical sub-alpine meadows, surrounded with stands of mountain pine Pinus mugo and Norway spruce Picea abies, followed upwards by sub-alpine beech forests.
On the very top of Snežnik we also met a group of 6 showy Alpine Accentors Prunella collaris that have just descended from the Alps, to spend the winter at lower elevations in karstic areas. Similarly also Wallcreepers Tichodroma muraria do this kind of seasonal migration and can be encountered in the same habitats, proven that there are enough cliff faces.
Finally some more landscapes: in the first pic is the gulf of Rijeka in Croatia with some of the Kvarner islands, as seen from the top of Snežnik, looking southwards. The second is a view south-eastwards to the mountains of Risnjak National Park in Gorski kotar (Croatia). The third photo shows a more unusual view on mount Nanos (the mountain that dominates the Karst and most of Primorska) with the Nanoščica river valley at its feet and the Julian Alps' mountain chain in the back. One of the best views for rounding up such a wonderful day!